sounds like a good order to try things, backup your NAND once you install bootmii to boot2 and you're covered

heres a few tips:
1. before you make a NAND backup with bootmii, backup your SD card is it will most likely be reformatted
2. after you make a NAND backup with bootmii, make sure to back up that nand.bin from your sd card to a safe location for future NAND recovery.
3. proceed with hacking!